A Comprehensive Review of Corrosion Resistance of Thermally-Sprayed and Thermally-Diffused Protective Coatings on Steel Structures

Protective coatings are widely utilized to promote corrosion resistance of the surfaces of steel components that are used in various industrial applications. Different surface engineering methods such as thermal spraying and thermal diffusion techniques can be used to fabricate these protective coatings. Thermal spraying processes have received significant attention due to their ability to deposit a variety of materials. Several metals such as zinc-, aluminum-, nickel, and chromium-based materials and their alloys can be deposited using thermal spraying processes to enhance the corrosion resistance and prolong the service life of steel components. On the other hand, technologies based on thermal diffusion techniques are emerging due to their unique deposition features, which alleviates the issues of cracking and delamination typical of thermal-sprayed coatings, as well as their ability to protect inaccessible and complex components such as the inner surface of long tubing and pipelines. This work is a comprehensive review on short and long-term corrosion resistance of the most effective and commonly-used coatings deposited by a variety of surface engineering techniques to protect steel structures. Moreover, the effect of the spraying process, the addition of alloying elements on the corrosion resistance of these coatings has also been reviewed in this study.